When Replacing A Breaker Panel, Would You Do this?

bedroom
in
It's hard to tell what's happened to a house's electrical system by the time
it's over 50 years old. Fortunately, I live in one of the first true
"developments" - cookie cutter houses built for office workers flocking to
DC for WWII work. There's always someone around who knew what the original
system looked like and the 88 year old guy who has been here since the war
he says these were 60A total panels with screw-in (4/15A) glass non-safety
fuses. I know there were fuses before I got here because I found the
color-coded safety types AND a safety-type that was a breaker, not a fuse.
That led me to believe they were alway having breaker tripping problems so I
was happy to replace two old 15A breakers with newer duals. Not only did I
gain a slot, I got new breakers with a known history.
--
Bobby G.

20A
only
I don't think I said otherwise. What I said was in relation to finding an
breaker too large for the circuit. It could easily allow enough current to
pass to cause a fire. That's what I found. Someone had put 20A breakers
that seemed pretty clear too large for the size wire they were connected to.
In that case, a 19.5A load wouldn't trip the breaker but would warm up the
in-wall wires pretty well, perhaps melting the insulation and causing an
arc. IIRC, that's why arc-fault breakers came into being. (-:
IMHO, to be completely sure, you need to inspect the panel to make sure that
all the wires pulled are of the same era if you want to use sizing as your
only guide. Even then, every obvious new addition to the panel is suspect,
especially if there aren't any matching inspection stickers. There's also
no way to tell whether some home electrician added four 150 watt floods to a
front door sconce circuit and has severely overloaded the circuit way
downstream of the wire at the panel. The older the house, the more likely
circuits have been tapped. That's why I mentioned investigating to see
which breakers were original to the panel. Tapped and overloaded outside
circuits might be fine in the cold weather and heat to the point of failure
at the peak of summer.
Ralph, let me ask you what would you think if you found an older panel (50
years old) with cloth covered wire that all looked to be about the same age
and gauge. They're hooked up to a mix of half 20A and 15A breakers with the
20A breakers being obviously much newer than any of the 15A breakers. The
20A breakers were all made 10 years after the panel. The 15A breakers have
the same manufacture date (almost) as the panel itself. (I'm excluded some
of the newer circuits that were obvious late-comers like central A and
grounded outlets near windows for window A/C's for the sake of simplicity.)

Wow. Ironically, we may see a time when devices become so efficient that
you can live on 40A all over again.
It's interesting how the patterns of electrical usage have changed.
Nowadays, since everything has a charger or line cord you can almost never
have enough outlets. I don't think I know a single person who doesn't use
multiple outlet strips throughout the house. In the modern kitchen, even
three 20 amp circuits might not be enough for some households.
--
Bobby G.

As stated above, the job is to replace the panel, not check out everything
in the house. I would look at the size of the wires and put in the correct
breakers for the wires leaving the panel. Then report to the home owner
what I found. Really report first, then let the home owner make the
decision on how much he wanted to spend.
Much the same when you take a car in for tires. If a mechanic finds other
issues such as bad breaks or out of alignment, he will change the tires, and
report the other issues to the car owner.

Sorry, but again, not when every circuit except for the dedicated
240 volt appliances were double tapped to the breakers, trying to
"decode" what went where when the old panel was packed full
of wiring running 25 something circuits off of only 16 breakers...
Totally not worth the time to figure that out -- since the proper
replacement of one circuit per breaker when the new panel goes
in it is a lot easier to figure out what is on the new circuits by
powering them up one at a time...
The old panel wasn't marked but for two or three of the circuits...
It is very nice that everyone here seems to think that tracing
every circuit and examining what every connection on it looks
like is included in a panel swap and service upgrade but it is
not... You will never know what the wiring is like in an existing
home looks like without opening every wall or pulling brand new
wires to every outlet box, switch box and light fixture and
abandoning the old wiring...
You can have a brand new panel with new home runs of brand
new wiring but in an old house you will have no clue what is
downstream, what the connections are and even where they
are located... Too often when an older home is gutted very
old knob and tube wiring is found with improper connections
tapped into it and junction boxes plastered over...
~~ Evan

news:80c7a3a0-2073-495d-8f33-
<stuff snipped>
<<It is very nice that everyone here seems to think that tracing
every circuit and examining what every connection on it looks
like is included in a panel swap and service upgrade but it is
not... You will never know what the wiring is like in an existing
home looks like without opening every wall or pulling brand new
wires to every outlet box, switch box and light fixture and
abandoning the old wiring...>>
I don't think anyone here was advocating tracing every wire and circuit.
They were mostly saying it's probably worth it to at least label what wire
went to which breakers, especially if there's more than one size of breaker
involved. Not doing so saves five minutes and loses information that could
actually save time and headache when putting in the new panel for some of
the very good reasons people have noted.
--
Bobby G.

The OP is correct. Just because a heavy gauge wire was used at the
panel does NOT mean that all the wiring from that point down to the
far end of the circuit is the same heavy gauge. What would happen if
there were a smaller gauge wire in the midpoint, and a heavy load
placed at the far end of the circuit. The breaker would hold, but the
smaller wire in the intermediate point of the chain would act as a
fuse (maybe), or maybe set the whole house on fire.

news:90525220-bd56-48b7-9ace-
<stuff snipped>
<<The OP is correct. Just because a heavy gauge wire was used at the
panel does NOT mean that all the wiring from that point down to the
far end of the circuit is the same heavy gauge. What would happen if
there were a smaller gauge wire in the midpoint, and a heavy load
placed at the far end of the circuit. The breaker would hold, but the
smaller wire in the intermediate point of the chain would act as a
fuse (maybe), or maybe set the whole house on fire.>>
What I've seen happen far too often is someone tapping into a circuit
instead of pulling a new wire from the circuit breaker box. While a light
circuit is probably no big deal, adding outlets can easily overload a
circuit in a way that causes wires to overheat in the wall. That's one of
the reason I mark outlets and fixed lighting loads on the inside door of my
circuit panel. It's a Word document I print out on card stock and revise as
necessary.
--
Bobby G.

NFPA somewhat saves you on 15 and 20a circuits with 240.4(D). A 14
gauge wire actually has an ampacity of 20a at 60c rating in 310.16 but
they make you put it on a 15a breaker to build in a <80% safety
factor. They know users may keep plugging in stuff until the breaker
trips, then unplug the clock to see if it will hold
I agree if you put a 20a continuous load on a 14 gauge wire it will
get warmer than it should but it really should not cause a fire.
The one you see in older houses, with fuses, that is really troubling
is the 30a fuse on that 14 gauge wire.

A am not sure the AFCI is detecting series faults reliably yet. They
had a hard enough finding intermittent shorting faults.
I think we are on AFCI version 4.0 now and there are still plenty of
the 1.0 versions out there.
It was a product that was rushed into the code and sold to the
customer at the point of a government gun, long before they were
perfected. The latest AFCI might find a loose connection at a device
termination but I wouldn't count on it.
The reason I have heard about limiting the stabbers to 14ga wire has
more to do with the forces involved in stuffing the device back in the
box. You end up bending the wire and deforming the contact.
I have never been a fan but as long as they are still listed, I have
to hold my nose and approve them.

I am certainly not advising that you should violate 240.4(D) the 14g 15a rule.

no
faults
The first bunch of GFCI's I bought back in the 80's (I think) were pretty
squirrely. The second batch of two I bought just a little later to replace
them have been running fine ever since. I think the originals were Slater's
and the replacements were Levitons.
I just read the section about arc faults at
http://www.interfire.org/features/electric_wiring_faults.asp
and it explained something that confused me because I did not know there
were two, perhaps three kind of arc faults. I did not know the series arc
decreases the current flow in the circuit so that a non AFCI breaker cannot
respond to the fault. It listed the primary causes of arcs as
carbonization of insulation (arc tracking), externally induced ionization
of air and short circuits. Gawd, lots of dangers out there I never even
knew existed! I know this is probably all old news to you, but I find the
various tests they perform to try to get electrical faults to ignite
fascinating. I can see why they were anxious to field a safety device that
at least tries to detect arc faults. The author claims it's one of the few
ways to cause actual ignition:
(1) arcing
(2) excessive ohmic heating, without arcing
(3) external heating.

That makes sense. I can't count the times I've seen outlets stuffed tighter
than the houses they show on "Hoarders." But wouldn't that bent contact
likely become a source of an arc fault since it's probably not able to carry
as great a current load as an undamaged switch?

From the research at the site above, they may not be listed forever. They
seem to be implicated in more than their fair share of home electrical
fires. Are outlets that don't use spring clips (just push it in) but
hold-down screws (push it in and screw down) both considered back stabs?
(That sounds obscene)

wire)
of
which
back-stabs
When you're inspecting outlets and receptacles, what do you look for? I mean
what's the most common screw-up made, especially by non-professionals?
--
Bobby G.

Are the screw down type equal in reliability to the curved wire end under
the screw type? They seem to be the best of both worlds - screw-down
reliability and (usually) a broad contact area (at least the kind I've seen
with the clamping plate).
Thanks for your input!
--
Bobby G.

The AFCI recognizes three different arc faults
#1 Faults inside the wall, (v 1.0)
#2 Faults from the cord cap to the usage equipment (v.2.0)
That is what the original definition of "combination" AFCI and the
early AFCIs only detected shorting faults.
#3 ... #3 ... Umm (sorry Rick)
The 3d fault is a series fault where you have a loose connection and
that was supposed to be detected in V 3,0
There are some revisions within those categories as they improved the
product and each manufacturer has their own proprietary method of
detecting faults. All AFCIs are not created equal.
Cuttler Hammer also has a GFCI/AFCI breaker that could be handy in one
of those places where both are required (IE a wet bar in a bedroom or
living room).

The back wired clamping device is not considered a back stab. They are
a little more expensive so a guy hitting a price point probably won't
use them if they are shaving costs.

I look at box fill, the grounding connection, the way the binding
screws are made up and if everything is connected to the right
terminal. It is one of those things that you know when you see it.
I am really looking at workmanship first. If this was done by someone
who is doing a good job, they usually do a good job everywhere. You
just look at a good representitive sample. The boss does not give you
time to open every box. That only happens when you see bad workmanship
or when you catch someone telling you a lie.
If I had to pick the single thing non-pros do wrong, it would be box
fill. They add a circuit to a box that was already close to or at the
limit.

That's why you put a junction box right outside the panel, combine 4
circuits, and then run one wire to a single breaker in the panel. No
concerns about exceeding the box fill specs. ;-)
Please, please note the smiley!

Panels are always rated for the maximum number of breakers you can
use. CTL panels have been in the code since the Johnson administration
will actually keep you from putting in too many "mini" or piggy back
breakers. Most of the time they will be rated for a full boat of
mini/piggies tho. You will see things like 20/40. That means 20 full
size slots or 40 dual breakers.
The place people get in trouble is when they try to wire a multiwire
(shared neutral) circuit to both sides of a piggy back breaker or a
pair of minis in the same slot. That overloads the neutral.
It should also be noted, there are a couple brands of breakers that
allow doubling up circuits on them. Square D is an example.

A total of 100 amps load on each line of the service is what a 100 amp
panel
can support... If your circuits are working at capacity then you
would only be
able to have a total of 100 amps being powered off each buss inside
the panel...
You can have MORE breakers in total theoretical load than the main
breaker
is rated for but if you exceed the main breaker rating it will trip if
the actual
loads on all the circuits being powered by the panel exceeds 100 amps
on
either line...
This is why load balancing is important, you want to evenly divide the
load
to both lines in your panel to ensure you don't experience nuisance
tripping
of the main circuit breaker...
~~ Evan

< A total of 100 amps load on each line of the service is what a 100 amp
panel can support... If your circuits are working at capacity then you
would only be able to have a total of 100 amps being powered off each buss
inside
the panel...>
I added about 5 20A circuits to my panel with "dual skinny" breakers which
brings the panel to the maximum it's rated for (100A) but they are never
used simultaneously and they, in fact, replace the older 15A circuits still
wired to the kitchen. I've tracked the maximum usage via the meter and the
house never draws much more than 60A, even with all the big loads going at
once. The question is - will it pass inspection or does the inpector have a
cutoff-point where he won't approve a panel whose individual breakers (face
value, not load) to some percent of the total rating of the panel?
<You can have MORE breakers in total theoretical load than the main
breaker is rated for but if you exceed the main breaker rating it will trip
if
the actual loads on all the circuits being powered by the panel exceeds 100
amps
on either line...>
That makes sense - what I am trying to determine is whether there's a point
at which an inspector will say "that's too many 20A breakers for this panel"
even *if* they are all powering very small loads.
<This is why load balancing is important, you want to evenly divide the
load to both lines in your panel to ensure you don't experience nuisance
tripping of the main circuit breaker...>
Way back when we had to rewire a number of PC's to run off dedicated
circuits because they fluttered when the main ventilation blower kicked off.
The electrician said it was because the load wasn't balanced.
--
Bobby G.
~~ Evan

Log in

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.